BirdAnalyst
Species · BCR 13 · BBS 2026 Release · 1966–2025

Common Grackle In Lower Great Lakes / St. Lawrence Plain

All regionsLower Great Lakes / St. Lawrence PlainGeneralists

Common Grackle in Lower Great Lakes / St. Lawrence Plain has fallen sharply: down 65% on the route-weighted index since 1968.

-65%Since 1968TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
86Routes In RegionSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
59YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable SignalsNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

long arc declinecomputed indexTrend sourceWhether the figure is our own computed route-weighted index or an official USGS modeled estimate. The current build labels every trend as computed.Full methodology →

Common Grackle has fallen sharply in Lower Great Lakes / St. Lawrence Plain: down 65% on the route-weighted index since 1968.

Common Grackle In Lower Great Lakes / St. Lawrence Plain Population Forecast

If the recent trend holds, Common Grackle in Lower Great Lakes / St. Lawrence Plain is projected to fall about 28% by 2030 — from 23 in 2025 to a central estimate of 17 (95% range 1.1–32). A 5-year backtest shows a typical error of ±6.1%, with 100% of held-out values landing inside the 95% band.

-28%Change by 2030TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
17Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
1.1–3295% range95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
±6.1%Backtest errorBacktest errorTypical error when we hold out the most recent years, forecast them, and compare to what actually happened. Lower means a more trustworthy projection.Full methodology →
If the recent trend holds, Common Grackle in Lower Great Lakes / St. Lawrence Plain is projected to fall about 28% by 2030 — from 23 in 2025 to a central estimate of 17 (95% range 1.1–32). A 5-year backtest shows a typical error of ±6.1%, with 100% of held-out values landing inside the 95% band.19662030
Projection of the recent trend (dashed) with 80/95% bands — a projection, not a prediction. Habitat, climate, and land use are not modeled.
YearProjected indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →95% low95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →95% high95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
2026215.337
2027204.236
2028193.235
2029182.134
2030171.132

Routes In Lower Great Lakes / St. Lawrence Plain

Routes recording Common Grackle in Lower Great Lakes / St. Lawrence Plain.
Recent countThe raw number of individuals recorded on this route in its most recent survey year. A single-route tally, not a trend.Full methodology →
PeruOHIO1381978
MacdougallNEW-YORK1122025
Slippery RkPENNSYLVANIA961994
GarrettsvileOHIO761991
RomulusNEW-YORK642000
HarmonsburgPENNSYLVANIA632025
NaplesNEW-YORK602025
HebronOHIO552025
Ballston LkNEW-YORK541995
OrleansNEW-YORK522025
PenfieldNEW-YORK492025
Cicero CtrNEW-YORK482025
New SomersetOHIO481993
N VictoryNEW-YORK441972
HamburgNEW-YORK422025
ChurchvilleNEW-YORK422025
AkeleyPENNSYLVANIA381979
LucerneOHIO372025
Harris HillNEW-YORK362025
HopkintonNEW-YORK352021
Canadice LNEW-YORK332025
North EastonNEW-YORK332025
Sugar GrovePENNSYLVANIA312025
BranchportNEW-YORK302024
PittsfieldOHIO302024

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.